Mr. Mills became sole owner of Osburn in 1985. In its early days, the company produced only wood stoves, and in 1980 it became the first-ever North American manufacturer to make a wood stove in compliance with Oregon State's strict air emission standards.

The company innovated yet again when it received EPA approval for a bay window-style wood stove and fireplace insert. The famous style was born, and is still present today, leaving its distinctive mark on many products, including the 1800-2200 series. For many years, the 2400 stove, with its 3.2 cubic foot combustion chamber, was the largest EPA-approved wood stove in the world. The company began exporting many of its models to the United States, and later to Australia and New Zealand. In 1988, the company became the first wood stove manufacturer to produce a gas stove. The new product was the first in a new line of gas stoves and fireplace inserts, including the Victorian Series, which are as remarkable as the company's wood-burning models. Some have the trademark bay window, another "first" for the industry.

Osburn Manufacturing was purchased by Stove Builder International (SBI) in 2002, and its operations were transferred to Quebec City in March 2003. SBI's operational efficiency and production capacity, combined with Osburn's design quality and combustion technology, have helped position the brand as a North American leader on the wood and pellet stove market.